The village of Armero in central Colombia was annihilated on the 13th of November 1985 by the Nevado del Ruiz volcano. As the eruption melted eight percent of the glacier situated upon the volcano, it caused a massive mudslide that engulfed the village, killing about 23,000 people.

Nowadays the Nevado del Ruiz volcano is keeping quiet, but it is still active. Geological deformation, electromagnetism or seismic activity can be useful in predicting whether an eruption may be imminent or not. The various craters of Nevado del Ruiz are regularly monitored by volcanologists, who use measurements of volcanic gas to make their predictions. Sulphur dioxide is particularly important for the scientists. The level of sulphur dioxide being emitted from the volcano can be an indicator for magma activity below the surface. Ordinary daily emissions of sulphur dioxide for a volcano like the Galeras, in southern Colombia, range from 1,000 to 3,000 tons. This can jump to 15,000 tons when magma rises to the surface. It is then at the point, when the magma blocks all cavities in the surface and sulphur dioxide is no longer expelled, that an eruption may take place.

Gustavo Garzón and his colleagues of the Colombian Institute of Geology and Mining have always climbed the Nevado del Ruiz to manually measure the flux of sulphur dioxide. Yet the climb is not always successful; low visibility and unstable snow-covered terrain can make the journey too dangerous.

To this purpose the research project NOVAC is devising a way to safely deliver real-time measurements of sulphur dioxide. Bo Galle is a Swedish physicist and coordinator of NOVAC. His team from Gothenburg have developed a prototype to monitor volcanic gas without having to make the risky climb to the crater. The prototype utilises new computing, optical spectroscopy and camera technology. The telescope within the unit is connected to a rotating mirror so that the volcanic gas plume that is emitted from the crater can be observed in different directions. The measurements are processed into data by the computers within the unit and sent by radio to observatories below. Developing a prototype that could withstand the large temperature fluctuations, storms, acid-rain and ashes from the volcano was very difficult for the research team. Because of the location of the installation, it must also be robust and require a minimum amount of maintenance.

More than 20 active and potentially dangerous volcanoes around the world, including two other Colombian volcanoes, now have such gas monitoring devices. Recent eruptions in Colombia have already been accurately predicted.

It was just a few years ago that several volcanologists were killed while measuring gas emissions in the Galeras volcano crater. Now volcanologists can safely use the data provided by the NOVAC project's prototype, which is updated every five minutes, for risk assessment. During the eruption of Nevado del Ruiz in 1985, the people were helpless. Today the constant flow of data provided could prove pivotal in saving human lives.